Grilled chicken marinated in sour milk

Ingredients:

• 1/4 cup firmly packed light brown sugar
• 6 cloves garlic, crushed
• 1 tbsp. coriander seeds
• 2 tsp smoked paprika
• 0.5 tsp + 1/8 tsp cayenne pepper
• 1 whole chicken (about 2 kg)
• 3 cups of sour milk or kefir
• 2 tablespoons unsalted butter
• 2 tablespoons apple cider vinegar
• 0.5 tsp ground coriander
• 1/4 tsp garlic powder
• Special equipment: rotisserie spit, meat string, or disposable tray

Preparation:

1. Brine:
   
   In a small saucepan, heat 1 cup water with 1/4 cup salt, brown sugar, garlic, coriander seeds, 1.5 teaspoons paprika, and 0.5 teaspoon cayenne pepper over low heat, stirring until the salt dissolves. Let cool completely. Place the chicken in a large zip-lock plastic bag. Pour in the brine and buttermilk, and seal the bag. Refrigerate for at least 4 hours or overnight, turning once or twice during this time.
2. About 30 minutes before grilling, remove the chicken from the brine and pat dry. Let it sit at room temperature.
3. Prepare the grill by installing the rotisserie spit according to the manufacturer's instructions. Preheat the grill to medium heat and prepare the indirect heat zone: on a gas grill, turn off the center burner(s); on a charcoal grill, rake the coals to the sides.
4. Combine the butter, vinegar, ground coriander, garlic powder, and the remaining 1/2 teaspoon paprika and 1/8 teaspoon cayenne pepper in a saucepan. Heat over low heat, stirring, until the butter melts. Set aside.
5. Tie the chicken with kitchen twine:
   
   Tie the legs together and tie the wings close to the body to create a rounded chicken shape. Once the grill reaches 160-175°C (325-355°F), place the chicken on the spit. Insert the tines of the spit into the chicken to ensure a tight fit; tighten the screws. If the string becomes loose, tie it again. Place the spit on the grill with the drip tray underneath. Turn the spit on.
   
   
   Move the coals to the sides of the grill and place a drip pan in the middle to catch any fat from the chicken and prevent flare-ups.
6. Cover the grill and cook, basting the chicken with the herb butter every 30 minutes, until a thermometer inserted into the thigh registers 165°F (74°C) and the skin is browned and crispy, 2 to 2 1/2 hours. If grilling on a charcoal grill, add coals as needed to maintain a temperature of 325°F (160°C) to 355°F (175°C).
7. Turn off the rotisserie. If using a gas grill, turn off all burners and let the chicken rest on the rotisserie for 10 minutes before carving. If using a charcoal grill, place the chicken on the rotisserie on a foil-lined baking sheet and let it rest for 10 minutes before carving.